youtrack
Nothing about a YouTrack project is guessable. Field names, their types, their allowed values, which of them are required, which transitions a state accepts, which link types exist, what a tag does when the issue resolves — every one of these is set per project or per instance, and every one changes what a write must contain. The API reference documents the shapes; only the instance knows the values. Read the project's configuration before the first write, and read it again after changing a field that governs another.
Success is not evidence that anything changed. A command request that asks for no field projection answers 200
with an empty body by design, so the response carries nothing to check. A create can partially fail, applying the issue
and silently dropping custom-field writes. A state write on a governed field can be refused by a rule. Read the issue
back after every write, and ask for a projection wherever the endpoint offers one.
An empty result never proves absence. YouTrack filters projects and issues hidden from AI tools out of MCP responses without signalling the omission, a collection read truncates at an instance cap when no explicit limit is set, and a query naming no sort returns the most recently updated issues rather than the most relevant. A duplicate search reports what was found, never what exists.